• Title/Summary/Keyword: Isolation effect

Search Result 1,045, Processing Time 0.031 seconds

Heavy-weight Impact Noise Reduction of Concrete Slab Reinforcement Using F.R.P (F.R.P 재료 보강에 의한 신개념 중량충격음 저감대책)

  • Jeong, Jeong-Ho;Yoo, Seung-Yup;Lee, Pyoung-Jik;Jeon, Jin-Yong;Jo, A-Hyoung
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2005.05a
    • /
    • pp.383-386
    • /
    • 2005
  • Low frequency heavy-weight impact noise is the most irritating noise in Korean high-rise reinforced concrete apartment buildings. This low frequency noise is generated by foot traffic due to the fact that Koreans do not wear shoes at home. The transmission of the noise is facilitated by a load bearing wall structural system without beams and columns which is used in these buildings. In order to control low frequency heavy-weight impact noise, floating floors using isolation materials such as glass-wool mat and poly-urethane mat are used. However, it was difficult to control low frequency heavy-weight impact sound using isolation material. In this study, reinforcement of concrete slab using beams and plate was conducted. Using the FEM analysis, the effect of concrete slab reinforcement using FRP(fiber-glass reinforced plastic) on the bang machine impact vibration acceleration level and sound were conducted at the standard floor impact sound test building. The $3{\sim}4dB$ floor impact vibration acceleration level and impact sound pressure level were reduced and the natural frequency of slabs were changed.

  • PDF

Isolation of Melanin Biosynthesis Inhibitory Compounds from the Flowers of Magnolia denudata (신이(辛夷)로부터 멜라닌 생성 억제물질의 분리)

  • Xu, Guang-Hua;Kim, Jeong-Ah;Park, Sung-Hee;Son, Ae-Ryang;Chang, Tae-Soo;Chang, Hyun-Wook;Chung, See-Ryun;Lee, Seung-Ho
    • Korean Journal of Pharmacognosy
    • /
    • v.35 no.2 s.137
    • /
    • pp.152-156
    • /
    • 2004
  • The bioassay-guided fractionation of the MeOH extract of the flowers of Magnolia denudata led us to the isolation of six compounds identified as fargesin(1), kobusin(2), aschantin(3), magnolin(4), rel-[7s,8s,8's]-3,4,3',4'-tetra- methoxy-9,7'- dihydroxy-8,8',7.O.9'-lignan(5) and oplodiol(6), respectively. Among the isolated compounds, fargesin(1) showed most potent inhibitory effect on the melanin polymer biosynthesis in cultured B-16 mouse melanoma cell lines$(IC_{50},\;45.7\;{\mu}M)$.

Effect of Depression and Anxiety on Symptoms in Thyroid Cancer Patients Undergoing Radioactive Iodine($I^{131}$) Therapy (고용량 방사성요오드($I^{131}$)치료를 받는 갑상선암 환자의 우울, 불안이 증상에 미치는 영향)

  • Chun, Nami
    • Asian Oncology Nursing
    • /
    • v.12 no.4
    • /
    • pp.297-304
    • /
    • 2012
  • Purpose: This study was to identify the symptom severity, interference and their psychological predictors in thyroid cancer patients hospitalized for radioactive iodine administration. Methods: One hundred seventy-seven thyroid cancer patients admitted to the isolation room for Iodine ($I^{131}$) therapy were recruited. Subjects were asked to complete the questionnaire on core symptoms, thyroid cancer symptoms, interference, depression and state anxiety in the evening after receiving radioactive iodine therapy. Data was analyzed using frequency, percentage, mean, Pearson's correlation, and multiple regression with SPSS vs. 19. Results: Lack of appetite, drowsiness, sleep disturbance, fatigue, and nausea were the 5 most core symptoms. More than 20% of patients experienced moderate to severe thyroid cancer symptoms including feeling cold, hoarseness, swallowing difficulty, and feeling hot. More than 30% of subjects experienced moderate to severe interferences in mood, general activity, and 22% in walking. Depression and state anxiety were identified as predictors of core symptoms, thyroid symptom severity and interference. Conclusion: Nursing interventions to reduce the symptom severity and interference need to be developed by considering thyroid cancer patients' depression and anxiety when hospitalized in the isolation room for radioactive iodine administration.

Internal Flow Dynamics and Performance of Valveless Airbreathing Pulse Detonation Engine (무-밸브 공기흡입 펄스데토네이션 엔진의 내부 유동과 성능)

  • Ma Fuhua;Choi J.Y.;Yang Vigor
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • 2006.05a
    • /
    • pp.367-370
    • /
    • 2006
  • This paper deals with the modeling and simulation of the internal flowfield in a valveless airbreathing pulse detonation engine (PDE) currently under experimental development at the U.S. Naval Postgraduate School. The system involves no valves in the airflow path, and the isolation between the inlet and combustor is achieved through the gasdynamics in an isolator. The analysis accommodates the full conservation equations in axisymmetric coordinates, and takes into account variable properties for ethylene/oxygen/air system. Chemical reaction schemes with a single progress variable are implemented to minimize the computational burden. Detailed flow evolution during a full cycle is explored and propulsive performance is calculated. Effect of initiator mass injection rate is examined and results indicate that the mass injection rate should be carefully selected to avoid the formation of recirculation zones in the initial cold flowfield. Flow evolution results demonstrate a successful detonation transmission from the initiator to the combustor. However, strong pressure disturbance may propagate upstream to the inlet nozzle, suggesting the current configuration could be further refined to provide more efficient isolation between the inlet and combustor.

  • PDF

Dynamic Stability Analysis of Base-Isolated Low-level Nonlinear Structure Under Earthquake Excitation (지진시 저층건물 면진구조의 비선형 동적 거동)

  • Mun, Byeong-Yeong;Gang, Gyeong-Ju;Gang, Beom-Su;Kim, Gye-Su
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.25 no.11
    • /
    • pp.1743-1750
    • /
    • 2001
  • This paper presents an analysis of nonlinear response of the seismically isolated structure against earthquake excitation to evaluate isolation performances of a rubber bearing. In the analysis of the vibration of building, the building is modeled by lumped mass system where the restoring force is considered as linear, bilinear and trilinear. Fundamental equations of motion are derived for the base isolated structure, and hysteretic and nonlinear-elastic characteristics are considered for a numerical calculation. The excitation levels are magnified fur the recorded strong earthquake motions in order to examine dynamic stability of the structure. Seismic responses (of the building are compared fur the each restoring force type. As a result, it is shown that the effect of the motion by the nonlinear response of the building is comparatively not so large from a seismic design standpoint. The responses of the isolated structures reduce sufficiently and controled the motion of the building well in a practical range. By increasing the acceleration of the earthquake, the yielding of the farce was occurred in the concrete and steel frame, which shows the necessity of the exact nonlinear dynamic analysis.

Vibration Related Branch Line Fatigue Failure (분기관 진동에 의한 피로파괴)

  • 전형식;박보용
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 1990.10a
    • /
    • pp.113-124
    • /
    • 1990
  • Tap lines are small branch piping generally less than two inches in diameter. They typically branch off of header piping having a much larger diameter. An example of a common tap line is a 3/4 inch size high point vent or low point drain. Most tap lines have at least one valve near the header tap connection to provide isolation. Two valves are often required for double isolation. A light water reactor(LWR) nuclear power plant will have several hundred tap lines. These lines come in many sizes and shapes and serve numerous functions. A single process piping valve may have three different tap lines associated with it (figure 1). Table 1 delineates the different categories of tap lines. Vibration failures of tap lines are a common occurrence in all industrial plants including nuclear and fossil power plants. These types of failures constitute a significant percentage of all piping related failures. An unscheduled plant shutdown or outage resulting from the failure of a tap line decreases plant reliability and may have a detrimental effect on plant safety. Most tap line vibration failures can be avoided through the use of appropriate routing and support techniques. Standardized designs can be developed for use in a myriad of applications. These designs will not only minimize failures but will also reduce the necessary analysis and installation efforts.

  • PDF

Vibration Reduction Using Wire Mounting - Test Results (Wire Mounting을 이용한 진동저감에 대한 실험 연구)

  • 최상현;박윤식
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2001.11a
    • /
    • pp.403-408
    • /
    • 2001
  • Structure-borne noise and vibration is one of the main complaints of home appliances such as refrigerators, washing machines, air conditioners, etc. There have been many efforts to reduce the emitting noise and vibration. Mostly the efforts have been concentrated to optimize the mounts shape and its material properties realizing that the vibration power is mainly transmitted to the structure via mounts. It is known that softer mounts have the better vibration isolation effect. But mounts have another important function in addition to the vibration isolation. That is to support the motor and compressor safely. Thus mounts should be stiff enough to resist the supporting items. But the two properties, stiff and soft, are contradict each other. So the designer should compromise the two complicity properties properly in between. Noticing that, motors and compressors themselves are very quite until they are connected to the base structure via mounts, wire connecting idea was proposed in this work. Instead of using conventional mounts, as shown in Fig 4, compressor was mounted using six wires as shown in Fig 5. Since wire is very flexible in bending but stiff in tension, we can realize the ideal mount design requirements, stiff enough to support and soft enough to isolate vibration power. The suggesting idea was tested with an air conditioner outdoor unit.

  • PDF

A Study on the Marital Power processes Perceived by Korean Urban Husbands (한국도시 남편이 지각한 부부권력 과정에 관한 연구-권력자원과 권력 과정을 중심으 로-)

  • 이정연
    • Journal of Families and Better Life
    • /
    • v.9 no.2
    • /
    • pp.267-284
    • /
    • 1991
  • The Purpose of this study is to explain marital power processes perceived by Korean urban husbands. To do the task, this study examined the possibility of classifying the power processes and the effect of resources by using resource theory and normative resource theory . The main results were as follows. 1) Power precesses are classified into five factors, such as, 'induction'. 'isolation' quarreling' 'carelessness' and 'withdrawal of love'. Induction, which makes control attempts by using verbal, indirect communication strategies, is proved to be the most factor. 2) Power resource variables are proved to be significant in their effects on the power processes. That is, objective are proved to be significant in their effects on the power processes. That is , objective resources are influencing on 'induction' and 'isolation' behavior and subjective variables are influencing on the other control attempts, Thus, it is found that including subjective variables as well as objective ones is very important. Above all, that the concept of the centrality of patriarchy is supported to be an appropriate concept for the study on the marital power processes i8s a fruitful result in research. But the variances explained by resource variables are relatively small. It is suggested. therefore, further study should include more significant subjective resource variables.

  • PDF

Effects of Infection Control Strategies for Vancomycin Resistant Enterococci in Intensive Care Units (중환자실에서 적용한 반코마이신(Vancomycin) 내성 장구균의 감염관리 전략 효과)

  • Choi, Kyung-Ok;Kim, Nam-Cho
    • Korean Journal of Adult Nursing
    • /
    • v.21 no.4
    • /
    • pp.435-445
    • /
    • 2009
  • Purpose: This study was to examine whether VRE infection control strategies have an effect on the decrease in incidence rates for VRE acquisition and VRE nosocomial infection in ICU. Methods: All the patients were examined for VRE carriers on ICU admission. Among them, patients hospitalized for over 48 hours were investigated for VRE acquisition rates and VRE nosocomial infection rate using VRE infection control strategies in ICU for the experimental group from September 2007 to April 2008. Before that, incidence of VRE acquisition and VRE nosocomial infection for the control group without Intervention were investigated from May to August 2007 retrospectively. Results: VRE acquisition rate in clinical specimens was 0.6% in the experimental group, that was significantly lower when compared to the control group. VRE carrier rate at admission to ICU was 15.4%. Out of 182 VRE carriers, 180 patients were identified by the active surveillance culture. Conclusion: These results suggested that active surveillance culture at admission was considered to be an essential measure for detection of VRE carrier. But without strict isolation and adherence rating after each intervention, hand washing and contact isolation alone did not significantly decrease VRE nosocomial infection, although it did significantly decrease incidence of VRE acquired from clinical specimen.

  • PDF

Development and Application of Modified Intermittently Aeration mode for Advanced Phase Isolation Ditch (APID) process at Winter Season (APID공정 내 동절기 개량형 간헐포기 운전모드 적용 및 개발)

  • Kwak, Sung-Keun;An, Sang-Woo;Chung, Mu-Keun;Park, Jae-Ro;Park, Jae-Woo
    • Journal of Korean Society on Water Environment
    • /
    • v.25 no.6
    • /
    • pp.872-878
    • /
    • 2009
  • Advanced Phase Isolation Ditch (APID) process was studied to develop economic retrofitting technology, for the plants where retrofitting of common activated sludge process is required. In this study, to develop and apply the modified intermittently aeration mode as process control conditions for treating municipal wastewater, a demonstration plant was installed and operated in the existing sewage treatment plant of P city. During this study, the average effluent $BOD_5$, SS, T-N, and T-P concentrations were 6.3, 4.5, 10.0, and 1.3 mg/L. The modified mode decreased the nitrification capability more than the conventional mode in the application period. Nitrate in the anaerobic condition can have a negative effect on biological phosphorus removal. In the decreasing nitrate levels, the modified mode increased the biological ability of removal phosphorus more than the conventional mode in this study. Therefore, newly developed APID process with modified intermittent aeration mode can be one of the useful processes for stable organic matter and nutrients removal.